Regulators across the globe have increased oversight of the financial sector, and banks' reputations have been battered by a series of scandals, including trying to manipulate key benchmark rates such as the Libor inter-bank lending rates.

"Apart from Libor and Euribor, BaFin is also looking into other benchmark setting procedures at individual banks such as for gold and silver prices," a BaFin spokesman was quoted as saying by WSJ Deutschland.

The report also said that similar investigations were under way in the United States and Britain, without citing sources.

Officials at BaFin were not immediately available to comment outside regular business hours.